[dpdk-dev] [RFC] ethdev: add IPv4/IPv6 DSCP rewrite action

[Suanming Mou <suanmingm@mellanox.com>]

For some overlay network, such as VXLAN, the DSCP field in the new outer
IP header after VXLAN decapsulation may need to be updated accordingly.

This commit introduce the DSCP modify action for IPv4 and IPv6.

Signed-off-by: Suanming Mou <suanmingm@mellanox.com>
---
 doc/guides/prog_guide/rte_flow.rst | 40 ++++++++++++++++++++++++++++++++++++++
 lib/librte_ethdev/rte_flow.h       | 31 +++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+)

diff --git a/doc/guides/prog_guide/rte_flow.rst b/doc/guides/prog_guide/rte_flow.rst
index a254c81..54b9250 100644
--- a/doc/guides/prog_guide/rte_flow.rst
+++ b/doc/guides/prog_guide/rte_flow.rst
@@ -2558,6 +2558,46 @@ the other path depending on HW capability.
    | ``mask`` | bit-mask applies to "data" |
    +----------+----------------------------+
 
+Action: ``SET_IPV4_DSCP``
+^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Set IPv4DSCP.
+
+Modify DSCP in IPv4 header.
+
+It must be used with RTE_FLOW_ITEM_TYPE_IPV4 in pattern.
+Otherwise, RTE_FLOW_ERROR_TYPE_ACTION error will be returned.
+
+.. _table_rte_flow_action_set_ipv4_dscp:
+
+.. table:: SET_IPV4_DSCP
+
+   +-----------+---------------------------------+
+   | Field     | Value                           |
+   +===========+=================================+
+   | ``dscp``  | DSCP in low 6 bits, rest ingore |
+   +-----------+---------------------------------+
+
+Action: ``SET_IPV6_DSCP``
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+Set IPv6DSCP.
+
+Modify DSCP in IPv6 header.
+
+It must be used with RTE_FLOW_ITEM_TYPE_IPV6 in pattern.
+Otherwise, RTE_FLOW_ERROR_TYPE_ACTION error will be returned.
+
+.. _table_rte_flow_action_set_ipv6_dscp:
+
+.. table:: SET_IPV6_DSCP
+
+   +-----------+---------------------------------+
+   | Field     | Value                           |
+   +===========+=================================+
+   | ``dscp``  | DSCP in low 6 bits, rest ingore |
+   +-----------+---------------------------------+
+
 Negative types
 ~~~~~~~~~~~~~~
 
diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
index 452d359..76bf080 100644
--- a/lib/librte_ethdev/rte_flow.h
+++ b/lib/librte_ethdev/rte_flow.h
@@ -2004,6 +2004,26 @@ enum rte_flow_action_type {
 	 * See struct rte_flow_action_set_meta.
 	 */
 	RTE_FLOW_ACTION_TYPE_SET_META,
+
+	/**
+	 * Modify IPv4 DSCP in the outermost IP header.
+	 *
+	 * If flow pattern does not define a valid RTE_FLOW_ITEM_TYPE_IPV4,
+	 * then the PMD should return a RTE_FLOW_ERROR_TYPE_ACTION error.
+	 *
+	 * See struct rte_flow_action_set_dscp.
+	 */
+	RTE_FLOW_ACTION_TYPE_SET_IPV4_DSCP,
+
+	/**
+	 * Modify IPv6 DSCP in the outermost IP header.
+	 *
+	 * If flow pattern does not define a valid RTE_FLOW_ITEM_TYPE_IPV6,
+	 * then the PMD should return a RTE_FLOW_ERROR_TYPE_ACTION error.
+	 *
+	 * See struct rte_flow_action_set_dscp.
+	 */
+	RTE_FLOW_ACTION_TYPE_SET_IPV6_DSCP,
 };
 
 /**
@@ -2530,6 +2550,17 @@ struct rte_flow_action_set_meta {
 	uint32_t mask;
 };
 
+/**
+ * RTE_FLOW_ACTION_TYPE_SET_IPV4_DSCP
+ * RTE_FLOW_ACTION_TYPE_SET_IPV6_DSCP
+ *
+ * Set the DSCP value for IPv4/IPv6 header.
+ * DSCP in low 6 bits, rest ignored.
+ */
+struct rte_flow_action_set_dscp {
+	uint8_t dscp;
+};
+
 /* Mbuf dynamic field offset for metadata. */
 extern int rte_flow_dynf_metadata_offs;
 
-- 
1.8.3.1